LV shower halogen switching from shower switch?

Guest

I will be buying an Aqualisa Axis Digital Pumped shower with an Aqualisa Dual (parallel) Switch to go outside the shower.
I want to have the shower light come on only when the shower is switched on (not only when the pump is switched on for boost).
Presumably the switch circuit is a safe low voltage. Could I wire a relay into that circuit which is LV switched but 240V switching?
What would be a suitable relay?